1884.] EDITOR'S BOX. 415 



' toot my ain horn,' even to the advantage of ' Eatho ' or any others who 

 may wish to know all about the dendrometer through the public prints ; 

 and it must lie in oblivion till it can raise itself by a good name, should 

 it be fortunate enough to procure such. I may, however, be permitted to 

 tell ' Ratlio ' that the instrument does its work, as was shown in the 

 drawings he referred to. It will take the height or length of any 

 object, from any position, whether from forty degrees below, or the 

 same above, the level of the object, and whether erect or leaning. It 

 will also find the distance to the object, if required. It only requires 

 one to work it ; it requires no calculations, as it indicates feet, yards, 

 chains, and miles in plain figures. It will take levels, measure 

 angles, and can be used in the field by the army as a range finder 

 and clinometer, and for field use : it is said to be superior to 

 Watkins's range finder and clinometer, two separate instruments by 

 that maker. 



On the advice of practical mathematicians, the instrument is 

 to be patented. As yet I cannot state the cost, as much will 

 depend on circumstances ; but I do not think it will exceed 

 35s. As to its being new, I can only hope it is, as it has so 

 entirely outgrown itself during the six years it has been in progressj 

 that nothing but the principle remains. The root of the principle is 

 not new, as it is found in ' Euclid ; ' but the application of the 

 principle is quite new, and was for the first time (so far as is known) 

 applied by Mr. Forbes, teacher, Clava Public School, Inverness-shire, 

 in 1877-8, to whom belongs the honour of originally inventing the 

 mode of application of the rule. This notice I consider due to the 

 gentleman referred to, for his courtesy to me in the matter. The 

 improvement and additions to its uses only belong to me as my share 



of the invention. 



D. F. Mackenzie. 



Morton Hall, Edinburgh. 



PINUS AUSTBIACA.i 



Sir, Since my remarks on the failure of some Pines of this 



variety, which appeared in your December number, I have observed 

 no allusion to the subject except that of Mr. Cannon's, in your 

 February issue, and he writes from Salbris, in France. 



He describes the particular district as mostly dry sand, and very 

 acid and more or less heathy, with an elevation of about 400 feet, 

 and nearly flat. He ascribes the failure of the Austrian Pine there 

 to the absence of lime, and he asks me to state where I have found 

 them succeed and where to fall away. 



Preferring to my previous remarks, it was there stated that where 



